This invention relates generally to windshield wiper blade refill units of the type having a wiper element, a flexible backing strip having legs seated in grooves on either side of the wiper element and an end clip secured to one end of the backing strip for releasable connection with a supporting structure of a wiper blade assembly, and, particularly, to an arrangement for securing together the end clip and the backing strip of the refill unit.
A windshield wiper blade assembly typically comprises a blade refill unit releasably secured to a pressure distributing supporting structure which, in turn, is secured to the free end of a pivotally mounted arm assembly. When the wiper element of the blade refill unit becomes worn, it is desirable for the old refill unit to be easily disconnected from the supporting structure and replaced with a new refill unit.
To facilitate easy connection and disconnection of the refill unit and the supporting structure, end clips have been used which are secured to the backing strip and releasably engage with the claws of the supporting structure. These end clips comprise a planar body portion with two spaced arms extending therefrom which overlie the two legs of the backing strip and are seated therewith in grooves along both sides of the head of the wiper element. The arms have notches in their outer edges which resiliently engage the claws of the supporting structure and are released from engagement with the claws for removal of the refill units when the arms are squeezed together. To facilitate the squeezing by a person's fingers, the arms are often provided with tabs extending upwardly from the outer edges of the arms.
A troublesome problem of the refill units having end clips of the type described above lies in the manner in which the end clip and backing strip are secured together. Some current designs of end clips have projections at the end of the end clip extending through a slot in the backing strip to prevent relative longitudinal movement therebetween and the restraining action of the side walls of the grooves in the wiper element in which the two arms of the end clip are seated is relied upon to prevent relative motion in a direction normal to the longitudinal axis of the backing strip. When the arms of the end clip are engaged by the claws of the supporting structure, they are squeezed inwardly towards each other and fit snugly within the grooves. In this condition the restraining action of the grooves together with that of the claws of the supporting structure are generally sufficient to prevent the end clip from moving in a direction normal to the elongate axis of the backing strip and thereby becoming disengaged at its slot from the projection at the end of the backing strip.
However, when the refill unit is not secured to the supporting structure, and the end clip is in an unsqueezed condition, the arms of the end clip are sufficiently spaced that one or the other or both may move out of the grooves in the wiper element thereby permitting separation of the end clip and the backing strip where they are secured at their respective slot and projection. If the separation is great enough, the end clip may become totally separated from the backing strip and become lost.
Such separation of the end clip from the remaining portion of the refill unit may occur because of handling during the packaging of the refill unit such that incomplete and unusable refill units may be sold resulting in considerable consumer dissatisfaction. Further, when a plurality of such refill units are packaged together in a single container, dropping of the container has been known to result in separation of almost all of the end clips which, of course, requires considerable time to reassemble.